Originally Posted by bobc4d
why is the bottom of an aquarium glass? why isn't it metal or something unbreakable? along the same vein, how much weight will the bottom glass take?
The thing to remember is that you have the water dispersed over the entire bottom of the tank and it's not just in one spot.
You could do the math to figure out how much a gallon of water weighs, figure out the square inches for the bottom of your tank to determine the actual weight per square inch.
My tank is 48 x 13 or 624 square inches ( 40gal ) I have substrate at 70lbs, and lets say that it displaced 5 gallons of water.
A gl of water is 8.34 lbs so 35x8.34 = 291.90 +70 lbs = 361.9
That's my total weight with water and substrate. So 361.9 / 624 sq inches is 0.58 lbs per square inch.
When you take into effect that the glass is usually tempered, and depending on it's thickness, it's a very good choice as well as economical for the manufacturer.